my country has once again broken world records in ultra-high voltage (UHV) transformer manufacturing. On June 27, the first converter transformer for the Changji-Guquan ±1100 kV UHV project departed from the Changji TBEA UHV R&D base in Xinjiang and successfully arrived at the Changji converter station in the Zhundong Development Zone after a six-day journey. This project is reportedly the world's highest voltage level, largest transmission capacity, longest transmission distance, and most technologically advanced power transmission project, hailed as a pinnacle of power engineering. The arrival of the ±1100 kV high-voltage transformer marks the beginning of the core equipment installation phase at the Changji converter station.
Wang Jian, chief engineer of TBEA Co., Ltd. (hereinafter referred to as "TBEA") in charge of the project, introduced: "This ±1100 kV converter transformer is the world's first set of products. It is 33 meters long, 12 meters wide, and 18.5 meters high, with a single unit capacity of up to 607,500 kVA, which is 20% higher than the current world record for the highest transmission capacity." In recent years, Chinese transformer manufacturers have repeatedly developed products with "first-of-its-kind", "largest capacity", and "highest voltage level", breaking world records time and time again, demonstrating "Chinese creation" and "Chinese leadership" in the field of transformer manufacturing.
Meticulous manufacturing ensures high equipment quality
It is understood that the Changji-Guquan ±1100 kV ultra-high voltage direct current (UHVDC) transmission project has advantages such as strong transmission capacity, low loss, no need for synchronous operation of AC systems on both sides, and minimal damage to the power grid in the event of a fault. It is particularly suitable for long-distance point-to-point high-power transmission. As the starting point of this UHVDC project, the core equipment of the Changji converter station is the converter transformer, and its safe commissioning is crucial and essential for the project's success.
In May 2016, TBEA, leveraging its technological innovation capabilities and achievements in key projects, won the bid for all 14 high-end converter transformers at the Changji substation of the State Grid Corporation of China's Changji-Guquan ±1100 kV UHVDC project. Production of the project's products fully commenced in October 2017.
Zhang Xin, Party Secretary and Chairman of TBEA, introduced that the first ±1100 kV DC converter transformer for transmitting power was successfully trial-produced at TBEA on May 26 this year and passed all tests on the first attempt. In the factory test, the converter transformer's temperature rise, partial discharge, and other indicators were all better than the technical agreement and national standards, and it has been fully recognized by the customer.
Behind this major national project lies the wisdom and hard work of TBEA employees. "I have worked for 32 years and have built countless transformers by hand, but this is the first time I have built a ±1100 kV ultra-high voltage transformer. It is a rare experience and an honor in my life," said Ba Qingbin, who joined TBEA Shenyang Transformer Company in 1986.
The lead wire production team he led was the most critical part of the entire transformer production process. The thousands of crisscrossing leads were like the blood vessels of the human body; the slightest carelessness could lead to a major accident. Therefore, being extremely strict and meticulous became the working principle for him and his employees.
On the transformer body, leads of various sizes are arranged in an orderly manner with uniform spacing. Due to the special structure of the transformer, the lead-winding process is entirely done by hand. In the confined space, employees often have to squat, kneel, or bend over to wrap the insulation layer on the transformer. The transformer body is the largest component on the converter transformer. Its outer shell is made of a paper insulation material, which is very fragile. Any scratch during hoisting will cause the insulation performance of the product to deteriorate or even be scrapped. To ensure the smooth completion of the assembly of the ±1100 kV DC transmission converter transformer, TBEA staff repeatedly conducted assembly speed-up drills on the ±800 kV converter transformer.
To this end, TBEA invested in the construction of the world's largest and most advanced national ultra-high voltage engineering technology research center and ±1100 kV transformer R&D and manufacturing base during the project planning period.
Regarding on-site installation, according to Yao Bin, the project manager of the ±1100 kV Changji Converter Station, installing such a large-scale power equipment on-site is unprecedented, and the installation difficulty is a huge challenge for all technicians. The main difficulty in installation lies in the installation of the valve-side bushing, and the entire docking process requires extremely high precision.
The other 13 products have entered the production stage.
The successful trial production of a converter transformer at the Changji TBEA UHV production base marks a new era in the development of UHV power transmission technology worldwide. Currently, production of the high-end converter transformer for the Changji station of the ±1100 UHVDC transmission project has entered its peak period. The other 13 units have entered various stages of production. According to plan, all products will be completed and tested by the end of August and will be shipped to the site for installation, ensuring the project is operational by the end of the year.
Wang Jian stated, "The product shipped this time is the world's first set of products. It has a high voltage level, a large single-unit capacity, and is technically and industrially challenging. The production time is tight and the task is heavy, with strict requirements for the manufacturing environment and processing quality. TBEA regards this project as a lifeline project."
The ±1100 kV ultra-high voltage (UHV) project is the second UHV transmission project implemented by the state for "sending Xinjiang electricity to other regions," and it is also a new milestone in the history of world energy. The Changji converter station is the starting station of this second UHV transmission corridor for sending Xinjiang electricity to other regions. After its commissioning, it can transmit 66 billion kilowatt-hours of electricity to East China annually, equivalent to transporting 30.24 million tons of coal, directly creating an industrial output value of 19.8 billion yuan. It is of great significance for promoting the development of Xinjiang's energy base, advancing supply-side structural reform, driving economic growth, expanding employment, and achieving social stability and long-term peace in Xinjiang.
